If Barack Obama has fallen short of the expectations of many of his supporters, it is partly because they were so high to begin with. During his election campaign in 2008, Mr Obama spoke lyrically of “hope” and “change” and promised a new era of post-partisan politics. His unique status as his country’s first black president encouraged the sense that the limits of the possible had been redefined. Liberals embraced him as the man who would close Guantanamo Bay, bring peace to the Middle East and slow “the rise of the oceans”.

But Mr Obama did not reckon on the recalcitrance of a Republican opposition that has sought to undermine his presidency at every turn, or the intransigence of leaders such as Mahmoud Ahmadinejad and Binyamin Netanyahu. Four years on from his election, Guantanamo Bay remains open, the Middle East peace process has collapsed and the oceans have continued to rise. Yet, if the initial adulation for him was excessive, then so, too, is much of the subsequent disdain.

Mr Obama entered office in more difficult circumstances than any US president since Franklin D Roosevelt. The economy was in the deepest recession in 70 years and losing jobs at a rate of 750,000 a month; the automobile industry appeared destined for bankruptcy; the US was embroiled in a ruinous and unjust war in Iraq. It was, as we said at the time of his election, “the in-box from hell”. In view of this inheritance, he has performed creditably.

Early in his presidency, he acted to prevent another Great Depression by introducing a fiscal stimulus of $787bn, a mixture of tax cuts, infrastructure projects and increased unemployment benefits. Republican claims that the stimulus was “a failure” are entirely unsupported by evidence. A study by Mark Zandi, a former economic adviser to John McCain, and Alan Blinder, a former vice-chairman of the Federal Reserve, concluded that the policy had created or saved 2.7 million jobs and added 3.4 per cent to US GDP. The US economy has now grown for 13 consecutive quarters, a record that compares favourably with that of the austerity-fixated UK. A more appropriate criticism of the stimulus is that it was too small – yet it is doubtful that a bigger package would have passed Congress, and the final bill, 50 per cent larger in real terms than the entire New Deal, stands as a considerable achievement.

Similarly successful, as Nicky Woolf reports on page 18, was the government-led bailout of Chrysler and General Motors, an intervention dogmatically opposed by the Republicans. “Let Detroit go bankrupt,” declared Mr Obama’s opponent Mitt Romney in November 2008. Should he fail to win Ohio, a state that no Republican has ever won the presidency without carrying, that could be his epitaph.

It is in the sphere of foreign policy that Mr Obama has disappointed. While fulfilling his pledge to withdraw all US troops from Iraq, he has vastly expanded the use of predator drones in Pakistan, a form of warfare that is neither just nor efficacious. In the Middle East, he has been con­sistently outmanoeuvred by Mr Netanyahu, who, in violation of international law, has continued the expansion of Israeli settlements in the West Bank. Yet any temptation to suggest that the world can afford a defeat for Mr Obama is dispelled by the prospect of a Romney presidency. A victory for the Republican candidate, who, as Mehdi Hasan writes on page 38, has surrounded himself with Bush-era neoconservatives, would greatly increase the chances of war with Iran, embolden the most reactionary elements in Israel and further accelerate climate change.

On the domestic level, Mr Romney’s pledge to reduce government spending by a fifth would likely plunge the US into a double-dip recession, while his plans to cut taxes for the rich and slash spending on Medicaid, food stamps, housing subsidies and job training would result in a marked redistribution of wealth from the poorest to the richest. Mr Obama’s health-care reform act – his single greatest domestic achievement – would be repealed and Roe v Wade, the Supreme Court judgment that established the legal right to abortion, would be overturned. Let no one claim that there is nothing to choose between the candidates.

Mr Obama stands in a noble liberal tradition that supports an active state as a precondition for individual flourishing. His opponent, by contrast, stands for a shrivelled public realm in which the market rules all and the poor are treated with contempt. In order that the former vision may triumph, Mr Obama must be returned as president on 6 November and Mr Romney decisively rejected.